![Eric W. Biederman](/assets/img/avatar_default.png)
The current ipc shared memory code runs into several problems because it does not quite use files like the rest of the kernel. With the option of backing ipc shared memory with either hugetlbfs or ordinary shared memory the problems got worse. With the added support for ipc namespaces things behaved so unexpected that we now have several bad namespace reference counting bugs when using what appears at first glance to be a reasonable idiom. So to attack these problems and hopefully make the code more maintainable this patch simply uses the files provided by other parts of the kernel and builds it's own files out of them. The shm files are allocated in do_shmat and freed when their reference count drops to zero with their last unmap. The file and vm operations that we don't want to implement or we don't implement completely we just delegate to the operations of our backing file. This means that we now get an accurate shm_nattch count for we have a hugetlbfs inode for backing store, and the shm accounting of last attach and last detach time work as well. This means that getting a reference to the ipc namespace when we create the file and dropping the referenece in the release method is now safe and correct. This means we no longer need a special case for clearing VM_MAYWRITE as our file descriptor now only has write permissions when we have requested write access when calling shmat. Although VM_SHARED is now cleared as well which I believe is harmless and is mostly likely a minor bug fix. By using the same set of operations for both the hugetlb case and regular shared memory case shmdt is not simplified and made slightly more correct as now the test "vma->vm_ops == &shm_vm_ops" is 100% accurate in spotting all shared memory regions generated from sysvipc shared memory. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1087 lines
25 KiB
C
1087 lines
25 KiB
C
/*
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* linux/ipc/shm.c
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* Copyright (C) 1992, 1993 Krishna Balasubramanian
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* Many improvements/fixes by Bruno Haible.
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* Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
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* Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
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*
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* /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
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* BIGMEM support, Andrea Arcangeli <andrea@suse.de>
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* SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
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* HIGHMEM support, Ingo Molnar <mingo@redhat.com>
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* Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
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* Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
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* Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
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*
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* support for audit of ipc object properties and permission changes
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* Dustin Kirkland <dustin.kirkland@us.ibm.com>
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*
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* namespaces support
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* OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/init.h>
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#include <linux/file.h>
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#include <linux/mman.h>
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#include <linux/shmem_fs.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/capability.h>
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#include <linux/ptrace.h>
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#include <linux/seq_file.h>
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#include <linux/mutex.h>
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#include <linux/nsproxy.h>
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#include <linux/mount.h>
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#include <asm/uaccess.h>
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#include "util.h"
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struct shm_file_data {
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int id;
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struct ipc_namespace *ns;
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struct file *file;
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const struct vm_operations_struct *vm_ops;
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};
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#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
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static const struct file_operations shm_file_operations;
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static struct vm_operations_struct shm_vm_ops;
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static struct ipc_ids init_shm_ids;
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#define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
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#define shm_lock(ns, id) \
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((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
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#define shm_unlock(shp) \
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ipc_unlock(&(shp)->shm_perm)
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#define shm_get(ns, id) \
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((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
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#define shm_buildid(ns, id, seq) \
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ipc_buildid(&shm_ids(ns), id, seq)
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static int newseg (struct ipc_namespace *ns, key_t key,
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int shmflg, size_t size);
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static void shm_open(struct vm_area_struct *vma);
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static void shm_close(struct vm_area_struct *vma);
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static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
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#ifdef CONFIG_PROC_FS
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static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
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#endif
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static void __ipc_init __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
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{
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ns->ids[IPC_SHM_IDS] = ids;
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ns->shm_ctlmax = SHMMAX;
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ns->shm_ctlall = SHMALL;
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ns->shm_ctlmni = SHMMNI;
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ns->shm_tot = 0;
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ipc_init_ids(ids, 1);
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}
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static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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if (shp->shm_nattch){
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shp->shm_perm.mode |= SHM_DEST;
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/* Do not find it any more */
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shp->shm_perm.key = IPC_PRIVATE;
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shm_unlock(shp);
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} else
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shm_destroy(ns, shp);
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}
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#ifdef CONFIG_IPC_NS
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int shm_init_ns(struct ipc_namespace *ns)
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{
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struct ipc_ids *ids;
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ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
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if (ids == NULL)
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return -ENOMEM;
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__shm_init_ns(ns, ids);
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return 0;
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}
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void shm_exit_ns(struct ipc_namespace *ns)
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{
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int i;
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struct shmid_kernel *shp;
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mutex_lock(&shm_ids(ns).mutex);
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for (i = 0; i <= shm_ids(ns).max_id; i++) {
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shp = shm_lock(ns, i);
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if (shp == NULL)
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continue;
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do_shm_rmid(ns, shp);
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}
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mutex_unlock(&shm_ids(ns).mutex);
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ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
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kfree(ns->ids[IPC_SHM_IDS]);
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ns->ids[IPC_SHM_IDS] = NULL;
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}
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#endif
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void __init shm_init (void)
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{
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__shm_init_ns(&init_ipc_ns, &init_shm_ids);
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ipc_init_proc_interface("sysvipc/shm",
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" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
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IPC_SHM_IDS, sysvipc_shm_proc_show);
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}
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static inline int shm_checkid(struct ipc_namespace *ns,
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struct shmid_kernel *s, int id)
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{
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if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
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return -EIDRM;
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return 0;
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}
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static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
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{
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return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
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}
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static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
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}
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/* This is called by fork, once for every shm attach. */
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static void shm_open(struct vm_area_struct *vma)
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{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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struct shmid_kernel *shp;
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shp = shm_lock(sfd->ns, sfd->id);
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BUG_ON(!shp);
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shp->shm_atim = get_seconds();
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shp->shm_lprid = current->tgid;
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shp->shm_nattch++;
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shm_unlock(shp);
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}
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/*
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* shm_destroy - free the struct shmid_kernel
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*
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* @shp: struct to free
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*
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* It has to be called with shp and shm_ids.mutex locked,
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* but returns with shp unlocked and freed.
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*/
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static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
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shm_rmid(ns, shp->id);
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shm_unlock(shp);
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if (!is_file_hugepages(shp->shm_file))
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shmem_lock(shp->shm_file, 0, shp->mlock_user);
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else
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user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
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shp->mlock_user);
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fput (shp->shm_file);
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security_shm_free(shp);
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ipc_rcu_putref(shp);
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}
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/*
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* remove the attach descriptor vma.
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* free memory for segment if it is marked destroyed.
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* The descriptor has already been removed from the current->mm->mmap list
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* and will later be kfree()d.
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*/
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static void shm_close(struct vm_area_struct *vma)
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{
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struct file * file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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struct shmid_kernel *shp;
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struct ipc_namespace *ns = sfd->ns;
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mutex_lock(&shm_ids(ns).mutex);
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/* remove from the list of attaches of the shm segment */
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shp = shm_lock(ns, sfd->id);
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BUG_ON(!shp);
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shp->shm_lprid = current->tgid;
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shp->shm_dtim = get_seconds();
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shp->shm_nattch--;
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if(shp->shm_nattch == 0 &&
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shp->shm_perm.mode & SHM_DEST)
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shm_destroy(ns, shp);
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else
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shm_unlock(shp);
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mutex_unlock(&shm_ids(ns).mutex);
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}
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struct page *shm_nopage(struct vm_area_struct *vma, unsigned long address,
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int *type)
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{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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return sfd->vm_ops->nopage(vma, address, type);
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}
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#ifdef CONFIG_NUMA
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int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
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{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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int err = 0;
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if (sfd->vm_ops->set_policy)
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err = sfd->vm_ops->set_policy(vma, new);
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return err;
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}
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struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
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{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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struct mempolicy *pol = NULL;
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if (sfd->vm_ops->get_policy)
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pol = sfd->vm_ops->get_policy(vma, addr);
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else
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pol = vma->vm_policy;
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return pol;
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}
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#endif
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static int shm_mmap(struct file * file, struct vm_area_struct * vma)
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{
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struct shm_file_data *sfd = shm_file_data(file);
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int ret;
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ret = sfd->file->f_op->mmap(sfd->file, vma);
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if (ret != 0)
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return ret;
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sfd->vm_ops = vma->vm_ops;
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vma->vm_ops = &shm_vm_ops;
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shm_open(vma);
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return ret;
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}
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static int shm_release(struct inode *ino, struct file *file)
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{
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struct shm_file_data *sfd = shm_file_data(file);
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put_ipc_ns(sfd->ns);
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shm_file_data(file) = NULL;
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kfree(sfd);
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return 0;
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}
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#ifndef CONFIG_MMU
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static unsigned long shm_get_unmapped_area(struct file *file,
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unsigned long addr, unsigned long len, unsigned long pgoff,
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unsigned long flags)
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{
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struct shm_file_data *sfd = shm_file_data(file);
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return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, pgoff,
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flags);
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}
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#else
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#define shm_get_unmapped_area NULL
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#endif
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static const struct file_operations shm_file_operations = {
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.mmap = shm_mmap,
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.release = shm_release,
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.get_unmapped_area = shm_get_unmapped_area,
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};
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static struct vm_operations_struct shm_vm_ops = {
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.open = shm_open, /* callback for a new vm-area open */
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.close = shm_close, /* callback for when the vm-area is released */
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.nopage = shm_nopage,
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#if defined(CONFIG_NUMA)
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.set_policy = shm_set_policy,
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.get_policy = shm_get_policy,
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#endif
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};
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static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
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{
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int error;
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struct shmid_kernel *shp;
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int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
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struct file * file;
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char name[13];
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int id;
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if (size < SHMMIN || size > ns->shm_ctlmax)
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return -EINVAL;
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if (ns->shm_tot + numpages > ns->shm_ctlall)
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return -ENOSPC;
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shp = ipc_rcu_alloc(sizeof(*shp));
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if (!shp)
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return -ENOMEM;
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shp->shm_perm.key = key;
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shp->shm_perm.mode = (shmflg & S_IRWXUGO);
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shp->mlock_user = NULL;
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shp->shm_perm.security = NULL;
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error = security_shm_alloc(shp);
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if (error) {
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ipc_rcu_putref(shp);
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return error;
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}
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if (shmflg & SHM_HUGETLB) {
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/* hugetlb_zero_setup takes care of mlock user accounting */
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file = hugetlb_zero_setup(size);
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shp->mlock_user = current->user;
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} else {
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int acctflag = VM_ACCOUNT;
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/*
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* Do not allow no accounting for OVERCOMMIT_NEVER, even
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* if it's asked for.
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*/
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if ((shmflg & SHM_NORESERVE) &&
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sysctl_overcommit_memory != OVERCOMMIT_NEVER)
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acctflag = 0;
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sprintf (name, "SYSV%08x", key);
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file = shmem_file_setup(name, size, acctflag);
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}
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error = PTR_ERR(file);
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if (IS_ERR(file))
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goto no_file;
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error = -ENOSPC;
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id = shm_addid(ns, shp);
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if(id == -1)
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goto no_id;
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shp->shm_cprid = current->tgid;
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shp->shm_lprid = 0;
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shp->shm_atim = shp->shm_dtim = 0;
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shp->shm_ctim = get_seconds();
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shp->shm_segsz = size;
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shp->shm_nattch = 0;
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shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
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shp->shm_file = file;
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ns->shm_tot += numpages;
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shm_unlock(shp);
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return shp->id;
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no_id:
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fput(file);
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no_file:
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security_shm_free(shp);
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ipc_rcu_putref(shp);
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return error;
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}
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asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
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{
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struct shmid_kernel *shp;
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int err, id = 0;
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struct ipc_namespace *ns;
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ns = current->nsproxy->ipc_ns;
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mutex_lock(&shm_ids(ns).mutex);
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if (key == IPC_PRIVATE) {
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err = newseg(ns, key, shmflg, size);
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} else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
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if (!(shmflg & IPC_CREAT))
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err = -ENOENT;
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else
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err = newseg(ns, key, shmflg, size);
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} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
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err = -EEXIST;
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} else {
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shp = shm_lock(ns, id);
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BUG_ON(shp==NULL);
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if (shp->shm_segsz < size)
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err = -EINVAL;
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else if (ipcperms(&shp->shm_perm, shmflg))
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err = -EACCES;
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else {
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int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
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err = security_shm_associate(shp, shmflg);
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if (!err)
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err = shmid;
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}
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shm_unlock(shp);
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}
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mutex_unlock(&shm_ids(ns).mutex);
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return err;
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}
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static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
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{
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switch(version) {
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case IPC_64:
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return copy_to_user(buf, in, sizeof(*in));
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case IPC_OLD:
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{
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struct shmid_ds out;
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ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
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out.shm_segsz = in->shm_segsz;
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out.shm_atime = in->shm_atime;
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out.shm_dtime = in->shm_dtime;
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out.shm_ctime = in->shm_ctime;
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out.shm_cpid = in->shm_cpid;
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out.shm_lpid = in->shm_lpid;
|
|
out.shm_nattch = in->shm_nattch;
|
|
|
|
return copy_to_user(buf, &out, sizeof(out));
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
struct shm_setbuf {
|
|
uid_t uid;
|
|
gid_t gid;
|
|
mode_t mode;
|
|
};
|
|
|
|
static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
|
|
{
|
|
switch(version) {
|
|
case IPC_64:
|
|
{
|
|
struct shmid64_ds tbuf;
|
|
|
|
if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
|
|
return -EFAULT;
|
|
|
|
out->uid = tbuf.shm_perm.uid;
|
|
out->gid = tbuf.shm_perm.gid;
|
|
out->mode = tbuf.shm_perm.mode;
|
|
|
|
return 0;
|
|
}
|
|
case IPC_OLD:
|
|
{
|
|
struct shmid_ds tbuf_old;
|
|
|
|
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
|
|
return -EFAULT;
|
|
|
|
out->uid = tbuf_old.shm_perm.uid;
|
|
out->gid = tbuf_old.shm_perm.gid;
|
|
out->mode = tbuf_old.shm_perm.mode;
|
|
|
|
return 0;
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
|
|
{
|
|
switch(version) {
|
|
case IPC_64:
|
|
return copy_to_user(buf, in, sizeof(*in));
|
|
case IPC_OLD:
|
|
{
|
|
struct shminfo out;
|
|
|
|
if(in->shmmax > INT_MAX)
|
|
out.shmmax = INT_MAX;
|
|
else
|
|
out.shmmax = (int)in->shmmax;
|
|
|
|
out.shmmin = in->shmmin;
|
|
out.shmmni = in->shmmni;
|
|
out.shmseg = in->shmseg;
|
|
out.shmall = in->shmall;
|
|
|
|
return copy_to_user(buf, &out, sizeof(out));
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
|
|
unsigned long *swp)
|
|
{
|
|
int i;
|
|
|
|
*rss = 0;
|
|
*swp = 0;
|
|
|
|
for (i = 0; i <= shm_ids(ns).max_id; i++) {
|
|
struct shmid_kernel *shp;
|
|
struct inode *inode;
|
|
|
|
shp = shm_get(ns, i);
|
|
if(!shp)
|
|
continue;
|
|
|
|
inode = shp->shm_file->f_path.dentry->d_inode;
|
|
|
|
if (is_file_hugepages(shp->shm_file)) {
|
|
struct address_space *mapping = inode->i_mapping;
|
|
*rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
|
|
} else {
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
spin_lock(&info->lock);
|
|
*rss += inode->i_mapping->nrpages;
|
|
*swp += info->swapped;
|
|
spin_unlock(&info->lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
|
|
{
|
|
struct shm_setbuf setbuf;
|
|
struct shmid_kernel *shp;
|
|
int err, version;
|
|
struct ipc_namespace *ns;
|
|
|
|
if (cmd < 0 || shmid < 0) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
version = ipc_parse_version(&cmd);
|
|
ns = current->nsproxy->ipc_ns;
|
|
|
|
switch (cmd) { /* replace with proc interface ? */
|
|
case IPC_INFO:
|
|
{
|
|
struct shminfo64 shminfo;
|
|
|
|
err = security_shm_shmctl(NULL, cmd);
|
|
if (err)
|
|
return err;
|
|
|
|
memset(&shminfo,0,sizeof(shminfo));
|
|
shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
|
|
shminfo.shmmax = ns->shm_ctlmax;
|
|
shminfo.shmall = ns->shm_ctlall;
|
|
|
|
shminfo.shmmin = SHMMIN;
|
|
if(copy_shminfo_to_user (buf, &shminfo, version))
|
|
return -EFAULT;
|
|
/* reading a integer is always atomic */
|
|
err= shm_ids(ns).max_id;
|
|
if(err<0)
|
|
err = 0;
|
|
goto out;
|
|
}
|
|
case SHM_INFO:
|
|
{
|
|
struct shm_info shm_info;
|
|
|
|
err = security_shm_shmctl(NULL, cmd);
|
|
if (err)
|
|
return err;
|
|
|
|
memset(&shm_info,0,sizeof(shm_info));
|
|
mutex_lock(&shm_ids(ns).mutex);
|
|
shm_info.used_ids = shm_ids(ns).in_use;
|
|
shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
|
|
shm_info.shm_tot = ns->shm_tot;
|
|
shm_info.swap_attempts = 0;
|
|
shm_info.swap_successes = 0;
|
|
err = shm_ids(ns).max_id;
|
|
mutex_unlock(&shm_ids(ns).mutex);
|
|
if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
err = err < 0 ? 0 : err;
|
|
goto out;
|
|
}
|
|
case SHM_STAT:
|
|
case IPC_STAT:
|
|
{
|
|
struct shmid64_ds tbuf;
|
|
int result;
|
|
memset(&tbuf, 0, sizeof(tbuf));
|
|
shp = shm_lock(ns, shmid);
|
|
if(shp==NULL) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
} else if(cmd==SHM_STAT) {
|
|
err = -EINVAL;
|
|
if (shmid > shm_ids(ns).max_id)
|
|
goto out_unlock;
|
|
result = shm_buildid(ns, shmid, shp->shm_perm.seq);
|
|
} else {
|
|
err = shm_checkid(ns, shp,shmid);
|
|
if(err)
|
|
goto out_unlock;
|
|
result = 0;
|
|
}
|
|
err=-EACCES;
|
|
if (ipcperms (&shp->shm_perm, S_IRUGO))
|
|
goto out_unlock;
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock;
|
|
kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
|
|
tbuf.shm_segsz = shp->shm_segsz;
|
|
tbuf.shm_atime = shp->shm_atim;
|
|
tbuf.shm_dtime = shp->shm_dtim;
|
|
tbuf.shm_ctime = shp->shm_ctim;
|
|
tbuf.shm_cpid = shp->shm_cprid;
|
|
tbuf.shm_lpid = shp->shm_lprid;
|
|
tbuf.shm_nattch = shp->shm_nattch;
|
|
shm_unlock(shp);
|
|
if(copy_shmid_to_user (buf, &tbuf, version))
|
|
err = -EFAULT;
|
|
else
|
|
err = result;
|
|
goto out;
|
|
}
|
|
case SHM_LOCK:
|
|
case SHM_UNLOCK:
|
|
{
|
|
shp = shm_lock(ns, shmid);
|
|
if(shp==NULL) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
err = shm_checkid(ns, shp,shmid);
|
|
if(err)
|
|
goto out_unlock;
|
|
|
|
err = audit_ipc_obj(&(shp->shm_perm));
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
if (!capable(CAP_IPC_LOCK)) {
|
|
err = -EPERM;
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid)
|
|
goto out_unlock;
|
|
if (cmd == SHM_LOCK &&
|
|
!current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
if(cmd==SHM_LOCK) {
|
|
struct user_struct * user = current->user;
|
|
if (!is_file_hugepages(shp->shm_file)) {
|
|
err = shmem_lock(shp->shm_file, 1, user);
|
|
if (!err) {
|
|
shp->shm_perm.mode |= SHM_LOCKED;
|
|
shp->mlock_user = user;
|
|
}
|
|
}
|
|
} else if (!is_file_hugepages(shp->shm_file)) {
|
|
shmem_lock(shp->shm_file, 0, shp->mlock_user);
|
|
shp->shm_perm.mode &= ~SHM_LOCKED;
|
|
shp->mlock_user = NULL;
|
|
}
|
|
shm_unlock(shp);
|
|
goto out;
|
|
}
|
|
case IPC_RMID:
|
|
{
|
|
/*
|
|
* We cannot simply remove the file. The SVID states
|
|
* that the block remains until the last person
|
|
* detaches from it, then is deleted. A shmat() on
|
|
* an RMID segment is legal in older Linux and if
|
|
* we change it apps break...
|
|
*
|
|
* Instead we set a destroyed flag, and then blow
|
|
* the name away when the usage hits zero.
|
|
*/
|
|
mutex_lock(&shm_ids(ns).mutex);
|
|
shp = shm_lock(ns, shmid);
|
|
err = -EINVAL;
|
|
if (shp == NULL)
|
|
goto out_up;
|
|
err = shm_checkid(ns, shp, shmid);
|
|
if(err)
|
|
goto out_unlock_up;
|
|
|
|
err = audit_ipc_obj(&(shp->shm_perm));
|
|
if (err)
|
|
goto out_unlock_up;
|
|
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid &&
|
|
!capable(CAP_SYS_ADMIN)) {
|
|
err=-EPERM;
|
|
goto out_unlock_up;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock_up;
|
|
|
|
do_shm_rmid(ns, shp);
|
|
mutex_unlock(&shm_ids(ns).mutex);
|
|
goto out;
|
|
}
|
|
|
|
case IPC_SET:
|
|
{
|
|
if (copy_shmid_from_user (&setbuf, buf, version)) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
mutex_lock(&shm_ids(ns).mutex);
|
|
shp = shm_lock(ns, shmid);
|
|
err=-EINVAL;
|
|
if(shp==NULL)
|
|
goto out_up;
|
|
err = shm_checkid(ns, shp,shmid);
|
|
if(err)
|
|
goto out_unlock_up;
|
|
err = audit_ipc_obj(&(shp->shm_perm));
|
|
if (err)
|
|
goto out_unlock_up;
|
|
err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
|
|
if (err)
|
|
goto out_unlock_up;
|
|
err=-EPERM;
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid &&
|
|
!capable(CAP_SYS_ADMIN)) {
|
|
goto out_unlock_up;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock_up;
|
|
|
|
shp->shm_perm.uid = setbuf.uid;
|
|
shp->shm_perm.gid = setbuf.gid;
|
|
shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
|
|
| (setbuf.mode & S_IRWXUGO);
|
|
shp->shm_ctim = get_seconds();
|
|
break;
|
|
}
|
|
|
|
default:
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
err = 0;
|
|
out_unlock_up:
|
|
shm_unlock(shp);
|
|
out_up:
|
|
mutex_unlock(&shm_ids(ns).mutex);
|
|
goto out;
|
|
out_unlock:
|
|
shm_unlock(shp);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
|
|
*
|
|
* NOTE! Despite the name, this is NOT a direct system call entrypoint. The
|
|
* "raddr" thing points to kernel space, and there has to be a wrapper around
|
|
* this.
|
|
*/
|
|
long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
unsigned long addr;
|
|
unsigned long size;
|
|
struct file * file;
|
|
int err;
|
|
unsigned long flags;
|
|
unsigned long prot;
|
|
int acc_mode;
|
|
unsigned long user_addr;
|
|
struct ipc_namespace *ns;
|
|
struct shm_file_data *sfd;
|
|
struct path path;
|
|
mode_t f_mode;
|
|
|
|
err = -EINVAL;
|
|
if (shmid < 0)
|
|
goto out;
|
|
else if ((addr = (ulong)shmaddr)) {
|
|
if (addr & (SHMLBA-1)) {
|
|
if (shmflg & SHM_RND)
|
|
addr &= ~(SHMLBA-1); /* round down */
|
|
else
|
|
#ifndef __ARCH_FORCE_SHMLBA
|
|
if (addr & ~PAGE_MASK)
|
|
#endif
|
|
goto out;
|
|
}
|
|
flags = MAP_SHARED | MAP_FIXED;
|
|
} else {
|
|
if ((shmflg & SHM_REMAP))
|
|
goto out;
|
|
|
|
flags = MAP_SHARED;
|
|
}
|
|
|
|
if (shmflg & SHM_RDONLY) {
|
|
prot = PROT_READ;
|
|
acc_mode = S_IRUGO;
|
|
f_mode = FMODE_READ;
|
|
} else {
|
|
prot = PROT_READ | PROT_WRITE;
|
|
acc_mode = S_IRUGO | S_IWUGO;
|
|
f_mode = FMODE_READ | FMODE_WRITE;
|
|
}
|
|
if (shmflg & SHM_EXEC) {
|
|
prot |= PROT_EXEC;
|
|
acc_mode |= S_IXUGO;
|
|
}
|
|
|
|
/*
|
|
* We cannot rely on the fs check since SYSV IPC does have an
|
|
* additional creator id...
|
|
*/
|
|
ns = current->nsproxy->ipc_ns;
|
|
shp = shm_lock(ns, shmid);
|
|
if(shp == NULL)
|
|
goto out;
|
|
|
|
err = shm_checkid(ns, shp,shmid);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
err = -EACCES;
|
|
if (ipcperms(&shp->shm_perm, acc_mode))
|
|
goto out_unlock;
|
|
|
|
err = security_shm_shmat(shp, shmaddr, shmflg);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
path.dentry = dget(shp->shm_file->f_path.dentry);
|
|
path.mnt = mntget(shp->shm_file->f_path.mnt);
|
|
shp->shm_nattch++;
|
|
size = i_size_read(path.dentry->d_inode);
|
|
shm_unlock(shp);
|
|
|
|
err = -ENOMEM;
|
|
sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
|
|
if (!sfd)
|
|
goto out_put_path;
|
|
|
|
err = -ENOMEM;
|
|
file = get_empty_filp();
|
|
if (!file)
|
|
goto out_free;
|
|
|
|
file->f_op = &shm_file_operations;
|
|
file->private_data = sfd;
|
|
file->f_path = path;
|
|
file->f_mapping = shp->shm_file->f_mapping;
|
|
file->f_mode = f_mode;
|
|
sfd->id = shp->id;
|
|
sfd->ns = get_ipc_ns(ns);
|
|
sfd->file = shp->shm_file;
|
|
sfd->vm_ops = NULL;
|
|
|
|
down_write(¤t->mm->mmap_sem);
|
|
if (addr && !(shmflg & SHM_REMAP)) {
|
|
err = -EINVAL;
|
|
if (find_vma_intersection(current->mm, addr, addr + size))
|
|
goto invalid;
|
|
/*
|
|
* If shm segment goes below stack, make sure there is some
|
|
* space left for the stack to grow (at least 4 pages).
|
|
*/
|
|
if (addr < current->mm->start_stack &&
|
|
addr > current->mm->start_stack - size - PAGE_SIZE * 5)
|
|
goto invalid;
|
|
}
|
|
|
|
user_addr = do_mmap (file, addr, size, prot, flags, 0);
|
|
*raddr = user_addr;
|
|
err = 0;
|
|
if (IS_ERR_VALUE(user_addr))
|
|
err = (long)user_addr;
|
|
invalid:
|
|
up_write(¤t->mm->mmap_sem);
|
|
|
|
fput(file);
|
|
|
|
out_nattch:
|
|
mutex_lock(&shm_ids(ns).mutex);
|
|
shp = shm_lock(ns, shmid);
|
|
BUG_ON(!shp);
|
|
shp->shm_nattch--;
|
|
if(shp->shm_nattch == 0 &&
|
|
shp->shm_perm.mode & SHM_DEST)
|
|
shm_destroy(ns, shp);
|
|
else
|
|
shm_unlock(shp);
|
|
mutex_unlock(&shm_ids(ns).mutex);
|
|
|
|
out:
|
|
return err;
|
|
|
|
out_unlock:
|
|
shm_unlock(shp);
|
|
goto out;
|
|
|
|
out_free:
|
|
kfree(sfd);
|
|
out_put_path:
|
|
dput(path.dentry);
|
|
mntput(path.mnt);
|
|
goto out_nattch;
|
|
}
|
|
|
|
asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
|
|
{
|
|
unsigned long ret;
|
|
long err;
|
|
|
|
err = do_shmat(shmid, shmaddr, shmflg, &ret);
|
|
if (err)
|
|
return err;
|
|
force_successful_syscall_return();
|
|
return (long)ret;
|
|
}
|
|
|
|
/*
|
|
* detach and kill segment if marked destroyed.
|
|
* The work is done in shm_close.
|
|
*/
|
|
asmlinkage long sys_shmdt(char __user *shmaddr)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma, *next;
|
|
unsigned long addr = (unsigned long)shmaddr;
|
|
loff_t size = 0;
|
|
int retval = -EINVAL;
|
|
|
|
if (addr & ~PAGE_MASK)
|
|
return retval;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
|
|
/*
|
|
* This function tries to be smart and unmap shm segments that
|
|
* were modified by partial mlock or munmap calls:
|
|
* - It first determines the size of the shm segment that should be
|
|
* unmapped: It searches for a vma that is backed by shm and that
|
|
* started at address shmaddr. It records it's size and then unmaps
|
|
* it.
|
|
* - Then it unmaps all shm vmas that started at shmaddr and that
|
|
* are within the initially determined size.
|
|
* Errors from do_munmap are ignored: the function only fails if
|
|
* it's called with invalid parameters or if it's called to unmap
|
|
* a part of a vma. Both calls in this function are for full vmas,
|
|
* the parameters are directly copied from the vma itself and always
|
|
* valid - therefore do_munmap cannot fail. (famous last words?)
|
|
*/
|
|
/*
|
|
* If it had been mremap()'d, the starting address would not
|
|
* match the usual checks anyway. So assume all vma's are
|
|
* above the starting address given.
|
|
*/
|
|
vma = find_vma(mm, addr);
|
|
|
|
while (vma) {
|
|
next = vma->vm_next;
|
|
|
|
/*
|
|
* Check if the starting address would match, i.e. it's
|
|
* a fragment created by mprotect() and/or munmap(), or it
|
|
* otherwise it starts at this address with no hassles.
|
|
*/
|
|
if ((vma->vm_ops == &shm_vm_ops) &&
|
|
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
|
|
|
|
|
|
size = vma->vm_file->f_path.dentry->d_inode->i_size;
|
|
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
|
|
/*
|
|
* We discovered the size of the shm segment, so
|
|
* break out of here and fall through to the next
|
|
* loop that uses the size information to stop
|
|
* searching for matching vma's.
|
|
*/
|
|
retval = 0;
|
|
vma = next;
|
|
break;
|
|
}
|
|
vma = next;
|
|
}
|
|
|
|
/*
|
|
* We need look no further than the maximum address a fragment
|
|
* could possibly have landed at. Also cast things to loff_t to
|
|
* prevent overflows and make comparisions vs. equal-width types.
|
|
*/
|
|
size = PAGE_ALIGN(size);
|
|
while (vma && (loff_t)(vma->vm_end - addr) <= size) {
|
|
next = vma->vm_next;
|
|
|
|
/* finding a matching vma now does not alter retval */
|
|
if ((vma->vm_ops == &shm_vm_ops) &&
|
|
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
|
|
|
|
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
|
|
vma = next;
|
|
}
|
|
|
|
up_write(&mm->mmap_sem);
|
|
return retval;
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
|
|
{
|
|
struct shmid_kernel *shp = it;
|
|
char *format;
|
|
|
|
#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
|
|
#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
|
|
|
|
if (sizeof(size_t) <= sizeof(int))
|
|
format = SMALL_STRING;
|
|
else
|
|
format = BIG_STRING;
|
|
return seq_printf(s, format,
|
|
shp->shm_perm.key,
|
|
shp->id,
|
|
shp->shm_perm.mode,
|
|
shp->shm_segsz,
|
|
shp->shm_cprid,
|
|
shp->shm_lprid,
|
|
shp->shm_nattch,
|
|
shp->shm_perm.uid,
|
|
shp->shm_perm.gid,
|
|
shp->shm_perm.cuid,
|
|
shp->shm_perm.cgid,
|
|
shp->shm_atim,
|
|
shp->shm_dtim,
|
|
shp->shm_ctim);
|
|
}
|
|
#endif
|